Knife-grinding machine.



F. HfLlaNDSAY I KNIFE GRINDING MACHINE.

APPLICATION. mm Nov. 23. m1.

Patented Mar. 11, 1919.

an smear FRED H. LINDSAY, OF CAMPELLO MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO ELLERY C WRIGHT, DOING BUSINESS UNDER THE FIRM NAME AND STYLE 0.?

WOOIDWARD & WRIGHT LAST COMPANY, OF BROCKTON, MASSACHUSETTS.

KNIFE-GRINDING acrame.

1,29q' 9"?9, Specification of Letters Patent. Patented ar. 11, 19115: Application filed November 23, 1917. Serial No. 208,505.

To allnvhom it may concern. complish this result, I mount the tool to be 55 l3e it known that I, FRED H. LINDSAY, a ground upon a constantly rotatin work citizen of the United States, and resident of support, rotating said WOllC support so that Campello, 1n the county of Plymouth and a new part of the knife is being constantly State of Massachusetts, have invented an brought into engagement with the rindin Improvement in Knife-Grinding Machines, medium, thus keeping the steel cool and per 60 of whichthe following'descript'ion, in con- ,mitting increased speed of the grindin menection with the accompanying drawings, is dium Without danger of iniury to the gutter a specification, like letters on the drawings edge. This provision oi" a rotary work representmg like parts. holder also, enables the machine to form ex- My present invention is an improved actly the same bevel completely around the 85 grinding machine intended particularly for curved portion of the cutter. Consequently forming a cutting edge on-the curved 'cutin turning lasts or similar uneven contoured ting portions of certain kinds of tools. The articles, the cutter knife will cut with unimachine is especially valuable for use in form accuracy entirely around its curved.

grinding the cutting edge on curved tools contour. This is of the greatest iu'aportantae used in turning lathes, such for example, in lathes, as the cutter constantly in opas those employed in the manufacture of eration on diiicrcnt parts of thecur vcd cutuneven formed articles, such as boot and ting surface, depending upon the contour of .shoe lasts. In the tools used in such lathes, the work, and unless a true beveled edge a curved cutting portion operates on the entirely around the circumference of the stockand it is of great importance to have curved portion is ground, the work will not the cutting edge true, and parallel with the be uniform. rear or back edge. Heretofore it has been My invention obviates all the difliculties 25 extremely difficult to sharpen, grind and true heretofore experienced in grinding this type the' cutting edge portion of such tools beof curved edge tool and I provide a machine cause this Work was done by hand, and be which will automatically and invariably cause of the diliiculty of grinding on the produce the same bevel on the curved. ,p'art inner part of the curved tool and forming of thecutter, grinding, truing and forming 30 the bevel around said curved cuttingedge' the edge of a cutter, accurately at the de- A. fnrther'important feature'of my pressired bevel, and also performing all subseent machine is, that having determined, by quent grinding actions on successive tools, I long experience and-exhaustive tests just the and successive grindings on the same tool, angle or bevel for greatest efficiency for the with exactly the same angle and accuracy. 3 particular tool on the special work in hand, My machine is simple, economical to my machine will always produce this bevel. build, and capable of use by unskilled labor. Thus, for example, in last turning lathes, The grinding operation is also greatly on it hasbcen found that the correct bevel or pedited while adjustments to compensate "for clearance on the cutters to operate upon wear in the grinder allow relative movekiln' dried rock maple, from which all lasts mcnt between the grinding medium and are made, is to have said bevel at an. angle work are provided. I of 35. Consequently for the grinding cut- In carrying out my present invention 1'. ters for this work I arrange the apparatus prefer to utilize a supporting base or castso that it will always produce a 35 bevel ing having a work holding member adapted 45 and no carelessness of the operator will vary to be rotated at relatively slow speed and this result. i with a rotatable spindle carrying the .A further important feature of 'my presgrinder adapted to be rotated at high speed, ent machine consists in the provision of said Work hol er and grmderbe 1. automatic means which will prevent the larly positioned, relatively with e' other, holding. of the grinding medium and the which angle is the bevel desired to be tool in one position too long, thus elimi formed on the edge ot' the cutter ln cutnating all danger of burning the steel tors used in last turning lathcs. this bevel is as Well as also eliminating the danger of, approximately thirty degrees, and therefore gouging the cutter at any point. To ac to form such a bevel on tho-cutting edge or t he tool, I arrange the axis of the work holder and the axis of the grinding medium at said thirty-five degree angle. I also pre-' fer to have the grinder adapted to be quickly withdrawn from contact with the work and readily replaced, to facilitate removal and 7 replacement of the cutter. I also provide work holding devices for the curved cutting tool so that the same Will be held accurately,

plained.

firmly and exactly in position for the grinding operation, as will 'be hereafter ex- Referring to the drawings, illustrating a preferred embodiment of my grinder,

Figure 1 shows a plan'vi'ew of the same Fig. 2 is a side view of my machine;

Fig. 3'is a fragmentary view of the work holder with a cutter knife in position and the cutting medium indicated in its relative position thereto; and

Fig. 4 1s a view of the curved cutting'tool to be ground.

' cal socket adjacent the machine.

I have herein illustrated the machine as adapted for electrical operation, viz., the rinding medium is mounted on a spindle adapted to be'rotated by a small electric motor with current supply cords leading to any suitable source of power, as

It will be understood that other mechanism to rotate the grinder spindle could be employed if desired. I also have hereinillustrated my machine as of a simple, compact, bench type of machine, wherein a standard or base 1 is formed with two armsyone arm 2 carrying the work-holding instrumentalities, and the other arm 3 being at an angle thereto of substantially thirty. degrees and carrying and supporting the grinding devices and adjustments.

are mounted standards 1 and 5 having journal bearings 6 and 7 for the shaft 8.,

Mounted on the-shaft 8 is awork=holding member in the form of a'wheel 9 with lugs 11 and 10 cast on the face thereof. The inner surfaces of these'lugs are rounded as shown at 13 and 14, being preferably in a curve of. the same radius as that of the curved portion of the tool to be held thereby. As shownin Fig. 3 a cutting tool 15 of the usual type is in position on the Work wheel 9, being held thereto by a headed bolt 16*engaging the shank of the tool 15 coming through the said shank, and with headed an electri- On the portion 2 clamped near its end the grinder 23. This motor is mounted on a longitudinal slide 25, adapted to be fed .toward and from the work holder 9 and slideways 26 and 27 by rotation of the hand wheel 28 turning the adjusting screw 29 in well-known manner. A .trans verse or cross-Wise movement is also given to'the motor by mounting the longitudinal carrier to slide transversely on the rods 32 and 33, being moved this way by the screw 34rotated by the-wheel 35 andhandle 36, this being a wellknown and ordinary constructionfor longitudinal and transverse adjustments.

In the operation of. the apparatus, the F wheel 28 is manipulated by the. handle 30 to withdraw the carriage holding'the motor 25 and the spindle 22 from immediate contact with the work'holder 9. A knife 15 to be ground is then applied to the work holder and adjusted with its curved portion in contact with the inner curved surface of the lug- 11, as herein shown.

The work}. holder 9 is then thrown into rotation by shifting the driving belt from 92 a the loose -to thefast pulley, said work holder rotating/at relatively slow speed. The motor 21 whichis now in operation rotating the spindle 22 and grinder 23 at high speed,

pireferably. twelve to eighteen hundred 95 P. M., is then moved forwardly by rotation of the feeding screw 29 and if desired moved laterally by manipulation of the side. feeding screw 3 1, until the grinder engagesthe knife, whereupon it is,held inv engagement until the grinding operation is completed. Rotation'of the work holder around the grinder forms the bevel around the entire surface of the cutting edge of the tool 15. It will be noted that it is necessary the grinder 23 of slightly less diameter than that of the curve in which the tool 14 is formed and in my machine, said grinder may: vary considerable in size, as it is worn ay, b fore it must be replaced by t n w 1 10 grinding medium. When so replaced, the threaded nuts 39 and 40, which clamp the grinder 23 between them, are adjustably threaded onto the end of the spindle 22 and are readily removed for changing the grinder, a lock nut 41 on the end being provided. It willbc noted that exactly the same bevel entirely around the cutting edge of the tool 15 is automatically formed and this bevel and edge'isicxactly reproduced on every succeeding tool ground thereon. By

the rotation ofthe work holder, the edge of the cutter is prevented from having one point in-contact with the grinding medium long enough to cause any damage, burning, or by gouging or otherwise distor-ting theedge. Furthermore, the steel being thus kept in motion and constantly cooled, the grinder can be rotated at very high speed, andthus acts more eiliciently. G

to have v as by 5 The exact position in which this grinder and Work holder are arranged, furthermore,

insures that the grinding edge of the cutter shall he at all times parallel with the original cutting edge and consequently parallel with the back of the knife. No matter how much the knife is ground down, the edge is always maintained true and thus parallel, which result is of great importance and is believed to be a distinct novelty in this art.

My invention is further described and defined in the form'of claims as follows:

I 1. A grinding machine of the .kind de scribed, adapted to operate on the curved cutting edge of a tool,'a support having two arms extending at a predetermined angle With each other, a rotatable Work holding grinding medium longitudinally and laterally toward and from said knife While main taining the grinding medium at the same fixed relative angle.

2. A grinding machine of the kind described, comprising a rotatable Work holder, :1 tool retaining lug on said work holder having a curved portion adapted to receive and hold the correspondingly curved portion of a cutting tool to be ground, a grinding medium adapted to be rotated at high speed and means to hold said grinding medium at a predeterminedfixed angle Withv regard to the edge of the tool to be grourd, sald grinding medium having a diameter less than that of the curved edge of said tool, and means to move the medium and tool toward and from each other at said predetermined fixed angle whereby the beveled face. ground on the tool will be at the same angle as that of the aixisof the grinder with the axis of the work holder.

In testimony whereoflhave signed my name to this specification. H. LINDSAY. 

